Control system for clothes dryers and combination washer-dryers



Jan. 14, 1958 J. w. TOMA ETAL 2,819,540

- CONTROL SYSTEM FOR CLOTHES DRYERS AND COMBINATION WASHER-DRYERS FiledMay 14, 1956 4 Sheets-Sheet 1 FIG.'

INVENTORS.

8| \JOHN w.-TOMA JOHN E. RYAN- THEIR ATT RNEY Jan. 14, 1958 r w. To ErAL2,819,540

CONTROL SYSTEM FOR CLOTHES DRYERS AND COMBINATION WASHER-DRYERS FiledMay 14, 1956 4 Sheets-Sheet 2 F'IG.3

a o cm JNVENTORS & JOHN w. TOMA JOHN 5. RYAN' THEIR ATTORNEY Jan. 14,1958 J. w. TOMA'ETAL CONTROL SYSTEM FOR CLOTHES DRYERS AND COMBINATIONWASHER-DRYERS 4 Sheet s-Sheet s Filed May 14, 195,6v

FIG.4

INVENTORS. & JOHN W. TOMA 4 JOHN E. RVAN' THEIR ATTORNEY J. W. TOMA ElAL SYS Jan. 14, 1958 2,819,540 CONTROL TEM FOR CLOTHES DRYERS ANDCOMBINATION WASHER-DRYERS Filed May 14. 1956 4 Sheets-Sheet 4 MW MW b000 F mh H .Y .HP v, TI..|I.IIIIWM.T.

pm w h 30%:gr www "H EJR ATTORNEY United States Patent CON TROL. SYSTEMFOR" CLOTHES DRYERS AND New York Application May-14, 1956, Serial No.secess- 9 claimst urea-45y Our-invention relates: to clothes dryers andmore partie ularly itrrelates to control systems fort-automatically:COI1itrolling. such. machines:- during: the. drying; operation; Whilethisinvention has general applicationto clothes dryers; it isparticularlyuseful imeornb-inati'on. clothes washing and dryingmachines.

Inwthes copending'aapplication of Walter E; Gray,.lr.,. S. N.512,612,.filedlune 2,2 1955,:and'1 assigned. to the same :a'ssignee as:the present invention, there is. describedand claimed. an .:improv'edl.control system for: combination washer-dryers. Thepwasher-di'yer ofthe Gray application: is provided With' tWOH separate. heating elements;for use duringithedryingtoperation and-thercontrol systernds so;arranged that both. elements are energized: at beginning. of: theoperation; However; toward theend ofi theaoperation one of the elementsis .de.energ-ized"-and the operation-1 is: completed on the reduced?power available, from the other. element alone. The reason forthiSsCOIIiIOhSBqUWlCG is that the predetermined maximumwattage availablefrom the twoheaters may. be advantageously used: for. moisatureextraction so lOHg'u-QS there. is surface moisture remaining on theclothes; But afte-r-thesurtacemoisture is removed, the maximum; Wattagesupplies moreheat. to. the machine than can. be usedi for theevaporation of the internal moisture .within the fabrics being dtiedwhereby if it were continued a rapid rise-in the-temperature within themachine would result... Themaximum -rate ot dryin-g of the internalmoisture within the fabrics .is not a direct.

function of the heatiappliedpbut rather. after acertain point inheatapplicati-on no. matterrhow much more-power. is appliedwithinereasonable 1imits,.the rate. of. evaporation will not increase...beyond that used formoisture extraction would oftcourse,

cause arise: in the temperature within the: machine. Thus inthe Graycontrol system l the power isreducedtoward the end of thedryingoperation,, .by the .de-energization.

of the: one heater, to. ava-Iue which etficiently removes. the moistureremaining... in the fabrics, without. causing, any overheating of. themachine- In other words byreducing the. power. only. enough heat. is.supplied to. evaporate efliciently. themoisture from, the!- fabrics.without any. ap-.-

trip. point the circuit. to the one heating element is opened so as to.de-energiize itfandlreduce the "heat applied to the clothes. Atthe.second trip point the second heating element is de-energizedand'the'operation of'themachine terminated. The secondjtrip pointis,of'course, selected attlie' temperature which" indicates the clotheshavedried;

The remaining-- increment of power:

'ice

i. e. which indicates that both the surface and the internal-moisture:have: been removed from the clothes. The first trip point isselectedra-ta temperature sufficiently below the secondxtrip pointstoinsure; that the power input is' reduced'1early-enoughio preventtemperature overshoot or heating of the machine beyond the second trip.point.

Our invention-hastfoirits primaryobject the provision of anewandimprovedfcontrol'. for the dryingtopertrtion. of a laundrywmachinewhieh control uses. a thermostathaving but a single trip point in orderfirst toreduce the power toward theend: ofwt-hew: drying operation; andthen to terminate the operation completely when the clothes: havefinishedadrying:atthe reducedpower: This control with thesingleleveldhermostaflnot only results in. a'shorter drying operationbut. also is less expensive due to a decreased LCOStEfOI" thethermostat.

Another objeetof-ourvinvention. is to provide" an improvedcontrol-system1 particularly adapted for use. in combinationwasher-dryersp which; utilizes a single level thermostat andtatimers.operated sequencecontrol mechanism first to apply full heat during thedrying operation, then toreduce theheat and. finally terminatetheoperationof the washer-dryer-after' a cool down period. The sequencecontrol mechanism. utilized. with the single level thermostatfor socontrolling. the drying operation may advantageously bettheosamemechanismasis used to control thewashing operation-of the washer-dryer.

In carryingout our invention in oneform thereof, we provide a.clothesdryert having clothestumbling means and a pair ofielectrioal.heating elements for supplying heat to the..clothes.,duringthe dryingoperation. lnthe washer-dryer we-incorporate anew. and improved controlsystem embodying our invention. This control system utilizes asingle-levelflthermostat and a timer operated sequencecontrolfmechanismior controlling the heating elements during thecdryingwoperation. The thermostat trips atapIedeteIminedhi-gh temperature andresets at a predetermined lower temperature, and. the thermostat and thesequence controlmechanism are so arranged in the system that thesystemenergizes-both the heating elements simultaneously at the. beginning. ofthe drying operation. until the thermostat trips for the first time-Thereby maximum power'is supplied tothe clothes during the firstpartoiftheoperation. After thethermostat resets after tripping the firsttime, .the system thenenergizes only one of the elmentsfor applyingreduced heat to the clothes. This reduced'heat application continuesuntil the thermostat. trips a second time in response to the reducedheat, and .atfthat pointthe system de-energizesthe second heater alsoand terminates thedrying operation. By this combineduseoffthe single.level thermostat and the sequence control mechanism whereby thethermostat trips twice at the same temperature for controlling theheaters, once to reduce the powenand the second time to terminatetheoperation otfthemachine, the system so energizes the heating elementsthat. a. relatively short drying time is produced. The short drying timeis,.ot' course, an ad vantageousfeature foricombination washer-dryers aswell as forclothes dryers. Also, the system is particularlyaclvantageouscost wiseiu' washer-dryers since it requires.

only the addition of an inexpensive single level thermostat to thesequencecontrol mechanism which must be provided anyway for the washing.operation.

The: subject matter Which.we regard as our invention. is.particularlypointed out. and distinctly claimedinthe" concluding portionof this specification.

Fig. l is a front elevational view of a combination washer-dryer, with aportion thereof being broken away to illustrate interior details;

Fig. 2 is a fragmentary cross sectional view taken on line 22 of Fig. 1;

Fig. 3 is a rear View of the machine with the rear panel removed toillustrate details;

Fig. 4 is a side elevational view of the machine, partially in sectionand with certain surfaces broken away to show details; and

Fig. 5 is a schematic electrical wiring diagram and sequence control camchart illustrating a control system for the machine, which systemembodies our invention in one form thereof.

eferring now to Fig. 1, I have shown therein a domestic laundry machinecomprising a combination washer and dryer. The operating elements of themachine are included within an outer cabinet structure including awrap-around central section 1. The central section 1 is supported on abase and toeboard assembly 2 and carries a separate top 3 provided withan integral backsplash panel 4. Access to the interior of the machine isprovided by a door 5 mounted on concealed hinges and opened by means ofa knee-operated latch control number 6.

The machine is so constructed that when a load of soiled clothes isplaced therein, it proceeds through a sequence of operations, firstwashing the clothes and then drying them. In order to provide completeflexibility of operation of the machine a number of operator controlsare included therein, these controls being mounted on the backsplashpanel 4. The controls include, for example, a plurality of push buttonsconsisting of an ofi button 7, hot and warm water buttons 8 and 9, adryer control or omit dry button 10, and a water heater button 11. Arotatable control knob 12 is provided for convenient operator selectionof any separate sequence of operation, and a second control knob 13 isincluded for operator selection of operating temperatures for the dryingportion of the cycle of operation. As will be seen hereinafter thesecontrols provide for complete flexibility of operation of the machine.

As shown in Fig. 4, the machine is of the horizontal axis type. That is,it has a clothes basket or drum 14 mounted for rotation on a generallyhorizontal axis within an outer enclosing tub structure 15. The basket14 comprises a cylindrical shell 16 which is closed at its rear end bymeans of a suitable wall or plate 17. The basket also includes a frontwall 18 which is formed so as to define an access or loading opening tothe basket. The basket is rotatably supported by a shaft 19 which ismounted in an elongated bearing 20 supported from the rear wall 21 ofthe tub. The tub is provided with an opening 22 in the front wallthereof, which is aligned with the access opening to the basket so thatclothes may be placed into or removed from the basket. The door 5 (seeFig. l) seals against a suitable gasket 22a to close this opening duringoperation of the machine.

During the operation of the machine the basket 14 is driven from anelectric motor 23 through a drive including a pair of flexible belts 24and 25 (see Figs. 2 and 3). The belt 24 connects the output pulley 26 ofthe motor 23 to the input pulley 27 of a transmission assembly 28. Thebelt 25 connects the output pulley 29 of the transmission assembly 28 toa basket drive pulley 30 mounted on the shaft 19 of the clothes-tumblingbasket 14. The transmission assembly 28 is of the multiple speed type,that is, the ratio thereof can be changed so that the basket is drivenat two different speeds. The transmission assembly thus provides onebasket speed for clothes tumbling and another basket speed forcentrifugal extraction. The ratio of the transmission assembly ischanged by means of a suitable spring biased, solenoid actuated plunger31. When the solenoid 32 controlling the plunger 31 is deenergized, thetransmission ratio is such that the basket is driven at a suitable speedfor washing and tumbling clothes, for example, 44 revolutions perminute. However, when the solenoid 32 is energized, the plunger 31changes the ratio of the transmission so that the basket is driven at asuitable speed for centrifugal extraction, for example, 200 revolutionsper minute.

During the operation of the machine the basket 14 is continuouslyrotated by means of this drive. The preferred sequence of operationsthrough which the machine proceeds to Wash and dry the clothes containedtherein is described hereinafter.

To heat the clothes during the drying portion of the cycle and also towarm the wash water during the washing portion of the cycle whendesired, there is provided in the machine a heater assembly includingtwo heaters 35 and 36. These heaters are mounted Within the upperportion of the tub 15 so that when energized, they heat the basket 14.The heating elements are preferably of the sheathed type in which aresistance wire is maintained in spaced relation with an outer sheath bya highly compressed, granulated, heat conducting, electricallyinsulating compound such as magnesium oxide. Such heating elements aresold under the trademark of Calrod and are available commercially. Whenthe heaters are energized during the washing cycle, they heat the waterby first heating the basket. Then as the basket dips into the wash waterat the bottom of the tub, it in turn heats the water. In other words,the rotating basket serves as an effective heat transfer means betweenthe heating elements and the water or other Washing liquid. When theheaters are energized during the drying cycle, the heat transferred tothe basket is then passed on to the clothes to cause vapor migration outof the clothes. Since the outer cylindrical shell of the basket isperforated some of the heat from the heating elements passes directly tothe clothes by radiation.

In order that the machine will not be damaged by the heat produced bythe heaters 35 and 36, it is necessary that the basket 14 be rotatingwhenever they are energized. If either of the belts 24 and 25 fail, thebasket 14, of course, stops rotating since it is then no longerconnected to the motor 23. Therefore safety means are provided withinthe machine whereby the heaters 35 and 36 are de-energized whenevereither of the belts fail. The safety means comprise a belt switch 37which is actuated upon the failure of either belt so as to de-energizethe heater relay 38 (Fig. 5) and thereby open the heater circuit. Thebelt switch 37 is arranged on a pivotally mounted sled 39 which supportsthe transmission assembly 28. Upon the failure of either of the beltsthe sled 39 is moved by spring biasing means attached thereto, and thismovement results in the operation of the switch 37. The arrangement ofthe sled 39 and the switch 37 is fully described and claimed in thecopending application of Daniel L. Duhamell, In, S. N. 526,413, filedAugust 4, 1955, and assigned to the same assignee as the presentinvention.

The means whereby water is admitted to and discharged from the tub 15during operation of the machine are particularly shown in Fig. 3. Thewater supply means includes connections 40 and 41 through which hot andcold water are supplied to the machine. For the washing operation avalve controlled by a solenoid 42 admits hot water to the machine and aValve controlled by an opposed solenoid 43 admits cold water to themachine. The hot and I cold water valves under the control of thesolenoids 42 and 43 discharge through a common outlet conduit 44. Fromthe conduit 44 the inlet water passes through a suitable air gap into afunnel 45. The funnel 45 discharges into a line 46 which leads into theinterior of the tub 15 through a suitable connection 47 (see Fig. 4).The break or air gap provided by funnel 45 makes it impossible for waterto be siphoned from the machine to contaminate the incoming water supplyline. In the illustrated machine a pressure actuated sensing device orwater level control 48 controls both the water solenoids as'reg-saaa 42and 43' tomaintain theproper watex level 'in the-mat chine during-thewashingoperation. This sensing'deviee issconne'cted to the interior'oftub by asuitab1eline49'l The illustrated mach-ine is of the type whichuses cold waterduring the di yingeycl -fop condensing the moistureextracted from the wet clothes. This condenser water-"is admitted: tothe machine through an additional" solenoid actuated val ve controlledbya= solenoid50 l(Fig: 3) The solenoid- 50 is energized-:3during-thedrying' operation so the valve passeswater at a slow rate'suificient' tocondense themoistu're' extracted from the clothesl As. shown, thecondenser water valve discharges into the funnel" 45 through a separateconduit SIL A-n air gap between conduit 5 1 'andt-he funnel preventssupply line contamination. From the funnel the condenser Water flowsthrough line 46 :and'conncctiom 47 into the tub. The condenserwaterflowing slowly" into the t'u b is spread o'ver the side of the tub by aninvertedv-sha'p'ed bead 52:(Fig; 4) formed onthetu'brwal-ldireetlybelhw'conneetion 47. The condenser water' 'beingsospread outcools a substantial portion of the area of the sidewallwhereby there isprovided a large' 'cool surface for condensingthe'moisture extracted from the clothes The wash}: and rinsewater usedduring the washing portion of the operation and the condenser water andthe moisture extractedfrom" the clothes during the drying operationiaredischarged from the machine through a sump 53 mounted "at the" bottomiofthe tub'; A suitable dischargehbse 54 leads-from--the fittingto amotordriven" drain pump-55" which discharges to the householddraiii; Theflow through the discharge line may; however, bacon trolled: by anysuitable means; as for example; by-a solenoid actuated drainvalve;

Referring now to the schematic circuit di'agramof Fig, 5, there"issh'owntherein a control syste'm for the com' binatiorr washer and dryerwhich embodies our inventionincon'c preferred form thereofl Thee onti-olsystem in eludes a timer operated sequence control mechanism gen= erallyindicated: at 56" anda single level thermostat 57. ThewthermOstatSTisactuated by mean'sof a sensing bulb 57a: within the tn b l f to which itis connected by means of a hydraulic line 57 (Fig; 3). The sensing bulb.57a comprises. a generally U-shaped member which is positioned: in 1 theair gap between the side wallof the tub and the'iouter surface of thebasket. Positioned inthe air gap therbulbsensesa temperature duringthedryiiig cycle which is correlated with the temperature ofthe clotheswithin the basket. The temperature at the thermostat bulb I is higherthan the clothing temperature but it rises and falls'with the clothingtemperaturesothatit can be used as an" indication thereof.

The thermostat 57 has a normal position and atripped position and initsnor mal position 'it closes one setof'contacts 59 andopens a secondset of contacts 60; whereas in its tripped position itclosescontac'ts60and opens the contacts 59. In other words it includes anormallyclose'd' set of. contacts 59- andanor1nallyopen setof contacts"60'.

- temperature within thetub and it resets at a predetermined lowertempertaure so as to open the contacts 60 and reclose the contacts 59.shown) may beincluded within the thermostatsovas to allow someoperatorselection: of the trip andaresctting temperatures: Thethermostat 5'7 is particularly used. in our control system to controlthe heaters 35 and 36 during, thedrying operation and alsoto control thelengthof the operation itself:

The sequence control meehanism'fitiis utilizedin"conjunction. with the lthermostat during the drying operation and it independently centreis themachine" duringwhe" Suitable biasing. means (not.

washing operatienz" The sequencecon'trol mechanism. is operatedbymeansof a suitable tinrermot0r62 and it ineludes a series' -of switches63 through 74 which are actuated 1 in the desired sequence by,appropriate switch operating means driven by the timer and indicatedschematieally bythe dihgranr75f Sequence: controls generally are wellknown, and several types are commercially available: Thereferegtherepresentation ofPig; 5.iS purely schematic; if being understood;however,. that each of the switches 63'7'4*- is*op'eratedfrom itsnormally open position to its-closedpositionby-means such as cams. Inthe particular*representation of FigLS it is to be understood thateachswitelhisconnected to' an" actuating means as indi'c'ate'dby the dotdashlines; the switches being closed during the periodsindicatedbytheheavy' black lines on the cam diagramt For example; switch63 is actuated to it's'elosed po'sition'on'the diagram from'points 11 to23. A

shows the l ength of the impulses'givento advance the camsin. theforward 'rotational direction. In other words, the ch'art TS maybeWega'rded for the purposes of this application'tobe'a development oftheperiphcries of the respective switeh operating earns; the heavy linesshowing the cam rises' which are effective to close respective switches?Fiirtherit will-be understood that the timer camsareprefrabljtjdi ivenwith an impulse or intermittent motion by means of asuitable mechanism(not shown) connectedlfbetwe'en them and the timer motor. Thus atswitchoverpoints-where-the chart 75 shows one switch opening' andanother closing; there isaouick make and break action so that one switchis closed simultaneously as 1 the other opened;

Further details withre'spect to, and the operation of our new and-eirnproved control system will become apparent by a review of a typicalsequence" of operation. Since our invention is particularly directed tothe control of the dryingoperation; the drying operation will beexplained first. Itwill be'understood; however; that normally the dryingoperationwill be preceded by and will follow automatical- 13/ theWashing-operation: Referring to the chart-75 it will be' see'n that thedryingfoperation begins at the point 27 of the scale and that atthatpoint the switches 65, 6'7, 68, 69} 7l' a'nd 74 of the sequence controlare closed. The remaining;switchesof" tho-control are open. With theseswitches closed both the heating elements 35 and 36, the drive motor 28,the condenser water valve solenoid 59, the drainpum-p SS'Tand-thetimermotor 62 are allenergized. Thepower for energ'izing these elementsis supplied from a three wirepower source comprising power supply lines76'and 7'7 and an'electrieal neutral line73i. This three wire-source mayfor example comprise the conventional 23Olvolt' domestic supply, havinga voltage of 230 volts between thesupplydines 76 and 77 and a voltage of115 volts between each of the power supply lines and the neutral. line-78.

With the above mentioned switches closed, the drive motor 28*isenergized-across the supply conductor 76 and.

the neutral line78i' Commencing'with the conductor '76,

thedtivemotor circuit extends through the main oif switch 7 and a dooroperated switch 79 to a conductor 86. The door operated switch 79comprises a safety switch which is closed Wheneverthe. door 5 is closedand which isopenedautomatically whenever the door is open, andbeing'connceted serially in the motor circuit it, of course,intermptsmotor. rotation whenever the door 5 is open. From the conductor80 the motor circuit continues throughthe omit dry switch 10, which isclosed since it is desired to'eonducta drying operation, tot the switch65 of'the sequence control. From theclosed switch 65 the circuit passesthrough a: conductor 81 to the lower contact 82.1of'the waterlevelswitchL48. Since thereis little ornowaterin the tub 15; the lowercontact 82 is engaged by thecenter movable contact83 of theswitch .sothat a circuit iseompleted therethroughL However, if the machine shouldbecome flooded i. e. should become partially filled with water, thecontact 83 will be actuated so as to disengage the contact 82 and closewith the upper contact 84 of the switch. This breaks the motor circuitand interrupts the rotation of the tumbling basket. The water levelswitch thus acts as a flood switch during the drying operation.

From the contact 83 of the water level switch the motor circuitcontinues through conductors 85, 86, and 87 to the start and runwindings 88 and 89 of the motor. The motor circuit is completed fromwindings 88 and 89 by means of a conductor 90 which is connected to theneutral line 78. The run winding 89 is connected directly to theconductor 90 and the start winding 88 is connected thereto through thecontacts 91 of a motor Centrifugal switch 92. When the motor 23 is atrest the contacts 91 are closed but as soon as the motor comes up tospeed, the switch opens the contacts 91 so that the motor operates themain winding 89 alone.

Energized through this circuit the motor 23 is efiective to drive thebasket 14 until such time as any one of the timer operated switch 65,the door switch 79 or the main switch '7 is opened. Flooding of themachine will also interrupt the motor rotation by the opening of thecontacts $2 and 83 of the water level switch 48. During the dryingoperation the basket should, of course, be driven at tumble speed andnot at centrifugal extraction speed and for that reason the shiftsolenoid 32 is de-energized. Specifically, the sequence control switch73 is open which breaks the circuit for the shift solenoid 32 andthereby causes the transmission to be set at its tumbling speed ratio.

Both heaters 35 and 36 are initiated at the beginning of the dryingcycle in order to apply maximum heat to the clothes as they are tumbled.In order to energize the heaters the heater relay 38 is energized bymeans of the sequence control switch 69 so as to close the relaycontacts or switches 93 and 94. The heater relay 38 specifically isenergized by a circuit between the supply conductor 76 and the neutralline 78. From the supply conductor 76 to the conductor 87 the circuit isthe same as the drive motor circuit. From the line 87 the relay circuitcontinues through the sequence control switch 68 and conductors 96, 9'7and 98 to the switch 69. From the switch 69 the circuit passes throughthe conductor 99, the belt switch 37 and the conductor 100 to the relay38 itself. From the relay the circuit is completed through conductor101, the contacts 102 of the motor centrifugal switch 92 and theconductor 90 to the neutral 78. The contacts 102 comprise a set of backcontacts in the motor centrifugal switch and are closed whenever thedrive motor is up to speed.

With the heater relay energized through this circuit the relay contacts93 and 94 are both closed for energizing the heaters. The heaterscomprise 230 volt heating elements and they are energized between thetwo supply conductors 76 and 77. Commencing with the supply conductors76 the heater circuit extends through conductort 103 and relay switch 93to a safety thermostat 184. The safety thermostat includes a pair ofcontacts 185' and 186 and so long as the temperature within the machineis at a safe temperature for the clothes being tumbled, the movableelement of the safety thermostat is closed against the contact 105.However, if an overtemperature condition should occur the movableelement closes against the contact 106. Assuming the temperature withinthe machine to be at a safe value, the heater circuit is continued fromthe contact 105 through a line 187 to the normally closed contacts 59 ofthe thermostat 57. The contacts 59 are closed until such time as thetemperature within the machine rises far enough to trip the thermostat57. The selection of this trip temperature will be explainedhereinafter. From the contacts 59 the heater circuit passes through aconductor 108 directly to the heating element 35. However, it passes tothe heating element 36 through the switch 74 of the sequence controlmechanism. The sequence control switch 74 is connected to the conductor108 by a line 109 and is in turn connected to the heater 36 throughanother line 110. From the heaters 35 and 36 the circuit is completedthrough the heater relay contacts 94. Energized through this circuit itwill be seen that both heaters will be energized together until suchtime as the thermostat 57 trips and opens the contacts 59. At that timeboth heating elements will be de-energized simultaneously. As will beexplained later our control system is so arranged that the sequencecontrol switch 74 never opens before the thermostat trips.

'In order to condense the moisture extracted from the clothes by theheating elements 35 and 36 the condenser water solenoid is alsoenergized at the beginning of the drying operation. The energization ofthe condenser water solenoid of course opens the condenser water valveand passes a steady flow of condenser water into the tub 15 through thefunnel 45, the conduit 46 and the fitting 47. This condenser waterentering the tub is spread out by the inverted V-bead 52 and flows downthe side wall of the tub in a thin film or sheet so as to cool the sidewall and condense the moisture extracted from the clothes. The condenserwater solenoid 50 like the drive motor is energized across the conductor76 and the neutral line 78. The circuit is the same as the drive motorcircuit to the line 87 and from the line 87 the condenser water solenoidis energized through the sequence control switches 68 and 67. Commencingwith the line 87 the condenser water solenoid is energized by a circuitthrough the switch 68 and connections 96, 97 and 98 to the solenoid 50itself. From the solenoid the circuit is completed through conductor111, timer operated switch 67, conductors 112 and 101, the back contacts102 of the motor centrifugal switch 92 and the conductor 90 to theneutral line 78. Energized through this circuit the condenser watervalve remains in operation so long as the timer operated switches 65, 67and 68 are closed and so long as the motor continues in operation. Ifthe machine should be flooded, the drive motor will be de-energized bythe water level control 48, and due to the action of the centrifugalswitch 92, this will result in the deenergization of the solenoid 50 andthe stoppage of the flow of condenser water. The opening of the timeroperated switch 65, of course, will de-energize the condenser watervalve at the same time as it ultimately de-energizes the drive motor.

Incidentally, it will be noted that a lamp 113 is connected in parallelwith the condenser water solenoid 50 so that it is energized wheneverthe solenoid is energized. This lamp 113 acts as a visual indicator toshow that the drying operation is in progress.

The drain pump is also energized during the drying operation in order todischarge the condenser water and the condensed moisture from themachine. The drain pump like the drive motor and the condenser watervalve is energized through the switch of the sequence control.Commencing with the closed switch 65, the circuit for the drain pumpextends through conductor 81 to the water level switch and thencethrough the contacts 82 and 83 of the switch and conductor to conductor86. Conductor 86 leads directly to the drain pump 55 itself and from thedrain pump the circuit is completed through conductor 111, timeroperated switch 67, conductors 112 and 101, contacts 102 of the motorcentrifugal switch and conductor to the neutral line 78. Energizedthrough this circuit the drain pump remains in operation so long as thesequence control switches 65 and 67 are closed, and so long as the drivemotor continues in operation. If the drive motor should cease runningthe drain pump will, of course, be de-energized by the centrifugalswitch at the same time as the heaters and the condenser water valve.

At the beginning of the drying operation the timer motor 62 is alsoenergized between the power supply 75 sesame,

and. the neutral; line: 78rso as] to: advance the operating. cams i. of1 the: sequencercontroll mechanisms Specifically, the timer 62,1iszene'rgizederthrn ugh thezsame circuit as: the drive/motor. to". theconductor? 87.. and.from thereit is energized: through. the. sequence:control switclr 72. The switch 72Jis' closed at .therbeginningzof. th'edrying operati'oncasz shownbin. the chart 75 an'd frlomi it thettimercircnitn continues through thevconductorszll l and 115 to': thertimermotor 62litself.. Fr'orn= thertimer motorthe. circuitisacompleted.ithrouglrconductors'116and 90 to thevneutralzline;78lEnergizedflin thisrnanner the timer motor: continues. to run' until?suchctime as. the; switch 72 opens;

Referring-to the: cam chartfit will" be-seenvthat the timer switchu72remainsmclosed only-briefly after the washer-'dryer'proceeds intothedrying cycle. Specifically, the;switch. 172' remains-closedenergizing the timer motor longgenoughsfortthe. timer motor: towcloseall. the other switches for the dryingjcycle i. ea, long enoughtfor ittor'clo'sel the-switches 68; .69 and 2 74, the: switches 65 and 67ubeingialready closed. Then the: timer'switch 72: opens upde-energizingthetimer motors Withthetimer motor de-energized the:contro1of the. heatingpelement and of the machineritself is their placedundertthe action of the thermostat 57.

During. this initial periodwthe-heating elements'35 and 36 arer, ofcourse,both energized to supply maxi-mum wattage for'heat-ing' theclothes Thesize' of the heaters will dependxupon'theparticular machineconstructed, but in; a size of .the' illustrated washer-dryer? suitablefor domestic use having a clothes? basket twenty-six. (26) inches indiameter it. haswbeen' foundthat. at-otal power ofr -fourthousand(4,000.) watts from: the two heating" units provides-a. satisfactoryamount ofxheat. forxmoisture.

extraction during thefirst stages ofifth'e. drying operation.

A total of 4,000 watts extracts moisture: from the clothesalsatisfactory rate without overheating the tub or any othenportiom. ofthe machine. For reasons explained below: the'si-zevof the heaters: isapportioned in this exemplary' machine so that the one"heaterfit'sisapproximately a twen-ty-eight hundred. (2,800) watt heaterand the other heater: 36' isapproximately a; twelve hundred (1,200) wattheater.

Both. heaters 35 and 36 remained energized applying maximum: heat; tothe clothes. until'such" time as the machine heats up farenough tocausethe thermostat 57' toatripp During thisperiod. of maximum: heaterpower application the machine: heats up slowly at first as the In fact,for a moisture is extracted from the: clothes; timellt-he heat suppliedmay be approximately equal to the heat iused for moisture extraction orevaporation and in:

that case aplateau may" even occur in the curve of the temperaturerise.However, once all the surface moisture is. evaporated from the clothes;thermachine thenibcgins to heat up rapidly. After the surface moisturehas been removed, themaximum wattage availablefrom' the two heaters,for: example 4,000 watts, is more than can be In other wordsall' of the4,000 watts, once the surfacemoisused to: extract'the moisture containedin the fibers.

ture has-been removed, does not cause evaporation'ot the moisture'fromthe fibers. R'ath'eronly a portion of this power can be used for theevaporation of the moisture from thefibers since it will "only evaporateat a certain maximum rate no matter how inuchtpower isapplied withinreasonable-limits. The fabricscandeliver moisture by 'capillary actionfrom the interior of the material to the from-:theheaters thereby causesthe machine to heatup natherrapidly'.

The trip p'oinflfor"the 'thermostat 57 is selected at a temperatureslightly above where this-rapid rise begin-s to occurl As=a-result whenthe machine is heated up to- 10 thetrippoint forthe first tim'e, allofthe surface moisture from the clothes has been: removed but" there isstill remaining 1 within the fibers of the clothesan appreciable amountof moisture. The heat has not been applied long enough after thesurface: moisture'is removed to evapo rate all of the moisture containedwithin theiibers'. However, to continue: the heating with both heatersenergized for a longer period of time would result in overheating of themachine andthe clothes: sothat even scorching of the clothes mightresult.

The trip point thus is selected at a-temperature slightly above that atwhich the surface moistureis allrernoved from the clothes. Forexample,intheillustrated machine it is contemplated that the thermostatwill'trip at 230 F. when a normal load of clothes is' being dried, thatis, a load substantially comprise'd' of cotton materials. For a load ofheavy fabrics such as'shagrugsand dungarees the trip point maybeselectedslightly higher since there is-more moisture-to be extractedfrom the fibers and since T they may be heated to a slightly highertemperature higher than the clothes temperature, as was mentioned above.

When the thermostat 57 trips'from'its normal position to its trippedposition, the thermostat contacts 59' are opened and the contacts 60 areclosed. The opening of the contacts 59' breaks the heater circuit sothat both heaters 35'and 36 are de-energi'zed. Thereby the machineimmediately starts to cool down; The simultaneous closing of thecontacts 60, however, energizes the timer motor 62 so that it begins tooperate again. Specifically, with the contacts 60 closed, the timermotoris again energized between the supply conductor 76 and the neutral line78. Commencing with the conductor 76 the timer motor circuit extendsthrough conductor 103, relay switch 93, the safety thermostat 104,conductor 107, and the now closed thermostat contacts 60 to a conductor117. The conductor 117 is connected to the conductor 114 and from therethe circuit is completed to the timer motor through the conductor 115.From the timer motor itself the circuit extends to theneutral line 78through the conductors 116 and Energized through this circuit the timermotor begins to drive the sequence control mechanism toward the offposition. Shortly afterit begins to run, i. e. at point 23 of the scaleof the cam chart 75, the timer causes the switch 72 of the sequencemechanism to close. This locks in the timer and continues it inoperation even if the thermostat should reset immediately"thereafter.Simultaneously, as it closes the switch 72' or slightly thereafterthetimer causes the sequence mechanism to open the switch 74. Theopening ofthe switch '74 breaks the circuit to the heating element 36whereby the heater 36 cannot be reenergized when the heater circuit isreclosed through the thermostat. After the switch 7 5 is open, thesequence control mechanism then continues to operate for" a period oftime, forexarnple, to a point slightly beyond'the point 30on' the camchart and at that point the switch 72 is again opened. Theopening of theswitch 72' again breaksthe timer motor circuit so" that the timer motoriS compIeteIy de-energized and the sequence control remains at astandstill.

During this operation of' the sequence control motor the machine iscontinually cooling down'dne to the de-energizatiotr of the-heatingelements. Atapred eterminedtem- V perture belowthe trip temperature. thecooling down of the machine results inaresettingof the thermostat 57.

In other words at that temperature the thermostat returns to itsoriginal or normal position reclosing the contacts 59 and opening thecontacts 66. The closing of the contacts 59 completes the heater circuitagain but now only the heating element 35 and not the heating element 36is energized. The above mentioned opening of the sequence control switch74 has removed the heating element 36 from the circuit. Thus in theabove mentioned exemplary machine only 2,800 watts and not 4,000 wattsare now applied to the clothes for the evaporation of the remainingmoisture contained within the fibEIS.

With the single heater 35 energized the drying opera tion continues at avery slow rate of rise or perhaps even with a temperature plateau. Theheat supplied from the single heating element is for the average sizeload of clothes approximately equal to the maximum wattage which can beutilized to extract moisture from the fibers. in other words heat issupplied from the single heating element at approximately the maximumrate which can be used for moisture evaporation from the fabrics. Thusthere is not a rapid heating up of the machine although the temperaturedoes rise slowly. This drying action continues until the trip point ofthe thermostat 57 is reached a second time. Normally the clothes aresubstantially dry when this temperature is reached. They may not becompletely dry, that is all the possible moisture may not be removedfrom them at that time, but a complete removal of the moisture is notnecessary for satisfactory drying. In fact, to prevent damage to theclothes it is desirable that a slight amount of moisture may even remainin them, for example an amount of moisture equal to approximately of thedry weight of the clothes. Thus it is contemplated that the trip pointhe so selected that the clothes will normally contain this 5% moisturecontent. when the trip point is reached. It will be noted, however, thatif all of the moisture should be removed from the clothes before thetrip point is reached, the machine will then heat up very rapidly to thetrip point and the heater 35 will be deenergized before any substantialoverheating and damaging of the clothes can result.

The tripping of the thermostat 57 for the second time again opens thecontacts 59 and closes the contacts 6%. The opening of the contacts 59,of course, de-energizes the heating element 35 and the closing of thecontacts (at) re-energizes the timer motor 62. The timer motor againbegins to drive the timer mechanism toward the oif position of thewasher-dryer. Shortly after the timer motor again goes into operation,the sequence control switch 72 is closed so as to lock in the timercircuit. Simultaneously with or slightly after the closing of the switch72, the switch 69 is opened. This opens the circult to the heater relayStl whereby the relay switches 93 and 94 in the heater circuit areopened. Thus even if the thermostat should reset, the heater circuit cannot be reclosed.

The machine continues in operation with the heaters off with the timermotor running so as to provide a cool-down period. In other words thedrive motor continues to operate the basket 14 for a timed period withthe heaters off so as to allow a cooling of the machine to a suitabletemperature for the removal of the clothes. Ultimately at the pointmarked Off on the cam chart the timer mechanism opens the switch 65. Theopening of the switch 65 de-energizes all of the elements of the controlincluding the timer motor, the drive motor, the drain pump and thecondenser water solenoid and thereby it completely terminates theoperation of the machine. The dry clothes may then be removed by theoperator.

From the above it will be seen that we have provided a new and improveddryer control in which a single level thermostat is used both to controlthe heaters and to determine the length of the drying operation. As aresult of the operation of the single level thermostat in conjunctionwith the sequence control mechanism, both heaters are initiallyenergized to apply maximum wattage to the clothes until the surfacemoisture has been removed therefrorn. At that time both heaters aredeenergized so as to allow the machine to cool down slightly. When thethermostat resets then only one heater is returned to operation so as toextract the internal moisture from the fibers of the fabrics. This isdone, of course, since both heaters supply more than enough heat thancan be used for the extraction of the internal moisture. When the trippoint of the thermostat is reached a second time under the heat suppliedfrom the single heating element alone, the internal moisture of thefabrics has been substantially removed. At that point the sequencecontrol mechanism is again energized so as to completely break theheater circuit, and then after a suitable cooldown period the operationof the machine is terminated. By this use of a single level thermostat arelatively inexpensive and simple control arrangement is povided. Alsoit results in the total wattage being applied during the earlier portionof the drying operation for the maximum possible time. Thus a shorterdrying operation is provided than has heretofore been possible.

It will be obvious that the thermostat differential between its trippoint and its resetting point is important to the functioning of thecontrol. If the di 'erential is too large, the thermostat will not havereset to reclose the contacts 59 and open the contacts 60 before switch72 is opened by the timer shortly after point 30 of the cam chart.Unless the thermostat has reset by that time, the opening of switch 72would not turn off the timer, rather it would still be energized throughcontacts 60 so it would continue to run. Thereby it would first openswitch 72 and then shortly thereafter reclose it. Once switch 72 isreclosed the timer is then, of course, energized continuously fromslightly before point 31 on the cam chart to the off position to timeout the operation no matter what the thermostat does. This would meansthe drying cycle would be quickly turned off without the reduced poweroperation taking place at all. Thus in order to obtain the reduced heatoperation of the cycle, the thermostat must reset before switch 72 isopened. In other words it must regain control by that time.

In our preferred embodiment using a 230 F. trip point, we arrange thethermostat so that it resets about 20 below the trip point, plus orminus 5. With the differential the thermostat ordinarily resets beforepoint 30 on the cam chart is reached and thereby the second or reducedpower period of heating is assured.

If the thermostat does not reset at this differential, it is normallybecause the clothes are already dry and do not need the second orreduced power period of heating. For example, a load composed ofdelicate synthetic fabrics may, unlike the heavier loads, besubstantially dry when the thermostat trips the first time. Beingsubstantially dry they are giving of]? little vapor or moisture wherebythere is poor heat transfer within the machine. As a result the machinedoes not cool down so rapidly when the heaters are turned oil. Thus, thethermostat does not reset until switch 72 has been reclosed at point 31,and the timer times the machine out. This is, of course, desirablebecause to apply more heat to the synthetic fabrics might result inover-drying. Thus our preferred differential not only assures that thereduced power operation will occur for those loads which need it, butalso prevents it from occurring for these loads which do not. Of course,if the thermostat differential is too small, then the reduced heatoperation would be effected for all loads, even for those delicatefabric loads which do not need it.

With regard to the safety features available during the dryingoperation, it will be noted that if either of the drive belts 24 or 25should break, the belt switch 37 immediately opens the circuit to theheater relay and com-- pletes a circuit for driving the timer motor tothe of position... Specifically Mlle: belt .swi-tcha breakerthe.;'heater relawcircuit between the. conductors: 99 and;100J'and.jlCQm7 plates. at timerrmotor circuithy connecting theconductor99.to: the"conductor 115. Energized-through thisicircuit; the timermotorwill. run continuously until-.-.suchltirne. as the control switch72 closeswtor SECOl'ldItliIlG4: The timer then. continues. in operationthrough thatswitch until it... opens .the. switch 65' to. deaenergize.all. the operating elements. of the machine. Thus it will. be. seenthatrifi either belt should break, therheaters zare.deaenergizediandthe. timer is caused torun 'continuously untilthemachine is...finally+shut off.

Iithemachine. should-become flooded, the. heaterwrelay circuitislikewise. broken and the. timer motor-energized. A150,. the. drivemotor,the. condenser. water valve 1and-the drain pump are (is-energized.Ifiitheamachinerbecomes floodedthewater levelzswitch. 48 --opens .thecontacts. 82 and-83 rand. closesathe: 'contactsr83 and- .84.. The.opening of the contacts -82.- and 83. breaks the heater relay circuitthe drive: motor circuit, the condenser water. solenoid circuits L and.the.v drain: pump circuit. The. closing of ithe. contacts. 8.3 and.84*,- however, energizes? the timenmotor. through. conductor. 1 17,.switch-;7.1.. ofi thexsequence .con:- trol and conductor- 115: The:switch 71*1ofr-thG sequence: control. is-so c arranged thatritaremainsscloseduntil such. time as; thelsequence control. switch. 72-.closes frthe1 seoondttimer Thenifi theqmachineiis stillsflooded. the. timerimotorshuts off .too; conversely if the. flood-i cone-- dit-ionrhaszcleared p;the machinewill then'. be timed. cutthroughthe. cool-down PBI'iOdl.

If the' machine shouldroverheat duringt-hevdnyingopr. erationathe safetythermostat. will. be: tripped sooas to: closethe conductor 1tl3-totheroontact.lflfir rather thani tot'the contact ltls. Thisu ofcourse,resultsin. the heater circuit. -1 being broken and further it energizes.the; timer motor through the conductors .117' and 1-15. Thus so. long;as the? over-temperature. conditions continues.. the. heaters:arcade-energized .andot-he timer: motor-.is iin operatiOH SGw' astoiidrive: the sequence controlr mechanisnntowandithe! oft f positionTo! complete? the? description. oil. the controhsystemof. Fig. 5 wewillanow. .explainahowiticonducts..theamachine. through. the washingoperation. prior to conducting. it. through. thedrying,operationndescribed. above... For that. purpose, lets it. i beassumed. initially that: the... sequence. control isvset inthe. spacejust. preceding. zero. on. the scalev ofirtlt'ecamchart,,.that.is,.-in.the. oihi position. Letwit. also bewassumed thatmain. switch. 7 is..manuallyclosed. andothat. the. door switch. .79 isclosed... While: cams. actua ated. switches 67,.6d and 72..are.. closed,no. powenisrsup p liedato anyof. the. electrical. componentsof.thepwasherdryer from .power. supply lines 76.. and -77 and. neutral.line-. 78a. To initiate thewashingaoperationz.thesequencecontrol isnon/manually advanced. tora position-slightly. bGYOHdLZQIO. As a resultcam actuated 1switches.6.'7',.68 and 72 are opened while switches 64;616;, 70 71and-74 areclosed. Closure ofswitch 66..completes...a.circuitto-.,-main.drive motor 28.;commencinggwithline 76..and.extending-through the main switch 7. and.door.switch79. to':lii1e8.0;1From: linethecircuit.continues-through. switch 6610"[116 conductorSGZcQnnectedi-tcr the drive motor; and from the drive. motor it. is.completed to new trall'line. 76'through conductor. 90. Inlthis mannerclo sure=rof the switch 66 causesoperation of themaindrivemotorrthroughout the period ofwopera-tion: of. the. apparatus-1 asac-:washing.machine. The. starting; Winding. 88 of' the=motor, ofcourse, remains inthe circuit only until motoir'comes up to speed;whereupon it-isdisconnected: blytheznrotor centrifugal switch 92.

Simultaneously with the; energization. oi the drive-moms anzaut'omaticwater. fill. control is: energizedthroughcam; actuated switch 66;Thisfill contro'lccomprises the water: va'lve' solenoids 42 and 43 andthewater :level switch 48: Tlle circuit for energizing the 'watenvalvesolenoids may? betraced through the :mainewitchfl; door switehaw, linestt-andtcamt aetuatedvswitchzoo to: the: linesvfife. and 86leadingq-tocontact 83 of the: water. level. switch assembly; 43;Asrmentioned above, contact 83: is. normally closed? with contact 82when thereis no liquidtin the machinegubut as thesliquid rises thehydro-static: actuating;means rises,.liftingcontaetSfi clear of contact82 and closing it withcontact 84: Thus when the machine. is empty a:circuit. is completed:* through the water. level switch to the line 81.connected at the contact 82. The line ulnleads to a conductor IIS-andthe:conductor 118 is connected to one terminal of. the hot watercontrol solenoid42. The opposite-terminal of the hot water sole:- noidis connected. through a line? 119" to i camwactuated switch 64, which"when. closed, completes; acircuit. to *line 129. Line120 is connectedtothexelectricali neutral. 78 through conductor 101, the normally opencontrctsxltli. of: the centrifugal switchwand conductor 9d to completethe water valve circuit. Fromthiscircuit it may be seen that theenergization of .the water valve". solenoidmiznis dependennfirstuponclosure: of actuated switch 66;. secondly; upon the closure oflcontactsand: 83 of thexwater levels-switch indicatingv that. the machine doesnot. have normal. liquid level; thirdlyupon closureofi cam' actuatedswitch 64; and-: finally upon closure of'contacts 192.01 the motorcentrifugal switch indicatingthatithe' machine is'operatin'g. at normalspeed. It will also he noted that coldwater: valve solenoid 43 may beenergized .simule taneously with the hotwater valve solenoid 42ibyclosure ofthe manual warm water switch9-f Switch 91mm.- pletes acircuit. from; line-118 to a liuellZl which is con-. nected to: onesideof the cold watenvalve solenoiduz43. The opposite terminalnotthesolenoidddsislconnectedivto line 119, and thus closure of manualswitch. iwenergiaes both hot and cold waterval-ve solenoids in.electrical par; allelto supply warm water to the machine.

The: timer motor 62. unlike thedriveniotordoesnnot begin to rotate .assoon as the control is turned; onf rather the timer motor 62. does not.commence; operation to advance the sequence: control untilnsuch' time asthe: machine. has been filled to normal. operating level. As the liquid:level in the machine'riseswater level: controlmeans 48 closes contacts83 and 84 whennormalnliquid' level is achieved. A timer circuit is then:completed from line through" cam switch 66, lines 86:and 35.; andcontacts 83 and 84 ofthewater level switch to the. line 117. The line117 is connected through cam actuiated switch .71 to line 115,. andlineis, of course; connected to one of the terminals of timer motorsdfls Thetimer circuit is completed fromthe: opposite terminal: of the timermotor to the electrical neutral. '78 through lines 116and 9L".

Inthe illustrated machine the heaters 35 and36 serve asta means formaintaining and. increasing the temperature of the Washing liquid aswell. as a means for. evap crating moisture during the drying cycle.While these: heaters, being mounted within the upper portion ofthe tub,as shown by Fig. 4, are not immersed in theliquid in the machine, thereis a substantial heattransferfrom: the heater to the rotating basket14.. Since'the: basket? dips into the liquid as it rotates, and. since'aconvective current is created, an effective.- heat transfer means isprovided between the electrical. heating elements and the washingliquid. Operation of the electrical heating; elements for maintainingand increasing. the liquid temperature is under the control of themanual heater switch 11 and cam actuated switch 70. caution, thiscontrol system is arranged so-thatthewater heating. means cannot beenergized unless the machinecontains normal operating level of liquid,unless. both drive belts: areoperative and unless the main. drive. motoris; rotating. at normal speed.

The: heaters are energized by means of the relay 38 which is'eflectivethe samepas in. the:drying operation to close switches 93 and 94.Heatingelement. 35 is..energized;.through the: relay switchesby" thesame-circuitas However, as a safety prein the drying operation, thecircuit commencing with line 76 and extending through line 103, switch93, safety thermostat 1M and line 197 to contacts 59 of the thermostat57. From the normally closed contacts 59 the circuit passes through line108 to heating element 35, and it is completed through relay switch 94to line 76. The other heating element 36 is energized through the samecircuit to line 103 and then through line 169, sequence control switch74, and line 110 to the heating element itself. From heater 36 thecircuit is completed through relay switch 94 to the other side of theline. Thus, when relay switches 93 and 94 are closed, both sections 35and 36 of the heating assembly are energized in electric parallel,assuming the safety thermostat 1M and the dryer control thermostat 57are both relatively cool and hence in circuit closed positions.

From the standpoint of the control system, the water heating means areenergized by applying power to the terminals of the operating coil ofrelay 38. This is accomplished by a circuit commencing with line 75 andextending through main switch 7, door switch 78, line 80, cam actuatedswitch 66, lines 86 and 85, contacts 83 and 84 of the water levelswitch, line 117, the manual water heater switch 11, cam actuated switch70, line 99, belt switch 37 and line 1069 to one terminal of relay 38.The opposite terminal of the relay is connected to line 101 whichcompletes the circuit to the electrical neutral 78 through thecentrifugal switch 162 in the main motor and line 94}. It is thus seenthat operation of the water heating means depends not only upon closureof the main switch and the door switch, but also of the water levelswitch, the manual water heater control switch, the cam operated switchfor the heater control, the belt switch, the contacts of the heaterrelay, and the safety thermostat. As shown, cam actuated switch '70remains closed for water heating to the first seven intervals as shownby cam chart 75. During this period of the washing operation the heatingcapacity is sufiicient actually to increase the temperature of thewashing liquid. This is desirable in many applications either toconserve the supply of the domestic hot water, or to supplement theheating capacity of the domestic hot water system. During the latterportion of the washing operation, the heaters are cycled on and off forshort periods in a manner calculated to maintain substantially the samewater temperature; or in other words, sufiicient heat is imparted to thewash water to compensate for thermal losses. At all times, of course,the operator may control operation of the water heater by means ofmanual heater switch 11.

As previously described, timer motor 62 advances the sequence controlduring the wash cycle commencing with that moment when the wash waterlevel switch signals that there is normal liquid level within themachine. At point 11 on the cam chart scale, the wash period terminates,and the spent wash water is discharged from the machine by the drainpump 55. The drain pump specifically is energized under the control ofcam operated switch 67. When switch 67 closes the pump is energized by acircuit from line 8h through cam operated switch 66, line 86, the pumpitself, line 1111, cam actuated switch 67, lines 112 and 101, the motorcentrifugal switch and line 9% to the electrical neutral.

It may be noted also that slightly prior to the closure of cam switch 67for pump operation, cam operating switch 72 closes in order to maintainthe sequence control timer motor in operation regardless of the positionof the water level switch 4-3. This is essential, of course, sinceotherwise the timer motor would cease operation Whenever the liquid isdrained from the machine. This auxiliary timer motor circuit may betraced from lines 76 and line through cam switch 66, line 87, camactuated switch 72 and lines 114 and 115 to the timer motor, and thenceto the neutral line as previously described.

Concurrent with the energization of drain pump 55, cam actuated switch63 is closed preparatory to the filling operation for the first rinse.Since it is adequate for the rinsing operations to have a mixture ofhalf hot and half cold water, cam actuated switch 63 functions toconnect both water valve solenoids in electrical parallel during rinsefill. Switch 63, as shown, is connected across the manual switch 9 forthat purpose.

Upon conclusion of the drain period, cam actuated switch 63 closes toinitiate the fill operation for the first rinse in a manner previouslydescribed in connection with the initial Washing fill. Cam actuatedswitch 72 is open, while cam actuated switch 71 is again closed so thatfurther operation of the timer motor is again dependent upon closure ofcontacts 83 and 84 of the water level switch when normal liquid levelexists within the machine. These circuits likewise were described inconjunction with the initial fill for the Wash period.

Following the first rinse, which is completed at point 14 on the camchart time scale, the first rinse water is drained from the machine byenergizing the drain pump 55 through cam actuated switch 67 aspreviously described. Again, cam actuated switch 71 opens while camactuated switch 72 closes to continue the sequence control drive inoperation in spite of the opening of the circuit through contacts 83 and84 of the water level control when water is drained from the machine.Adequate'time is provided by the sequence control from points 14 to 15on the cam chart scale for the water to be pumped from the machine. Atpoint 15 on the scale, cam actuated switch 73 closes to complete acircuit to the spin solenoid 37. Commencing with line 84) this circuitextends through switch 66, line 87 and a movable contact 122 of anunbalance switch 123 to a fixed contact 124. From there, the circuitcontinues through conductor 125, cam actuated switch 73 and conductor126 to spin solenoid 32. The opposite terminal of the spin solenoid isconnected through conductors 127 and to the electrical neutral 78. Theenergizing of the spin solenoid through this circuit, of course, shiftsthe transmission 23 so that basket 14 is driven at high speed to extractwater from the clothes.

If by chance the articles of clothing are distributed evenly around theinside of the rotating basket, the machine will rapidly accelerate thebasket to centrifugal extraction speed. If, however, due to unevendistribution, vibration of a predetermined amplitude exists, theunbalance switch will be actuated moving contact arm 122 away fromcontact 124 and into engagement with contact 128. The tub specificallyactuates the unbalance.

switch 123 to this result by means of a depending arm 129 (Fig. l)thereon. By the opening of the unbalance switch the solenoid 32 isreleased, and the machine returns to tumbling speed for re-distributionof the load. Simultaneously, however, from the back contact 128 of theunbalance switch a circuit is completed to an unbalance timer motor 130.The other terminal of this timer motor 130 is connected through a line131, the motor centrifugal switch and the line 90 to the electricalneutral 7 8. It will thus be seen that upon vibration exceeding apredetermined amplitude, the circuit to the spin solenoid is broken andsimultaneously a circuit is completed energizing the unbalance timermotor 130. Thus the machine slows down to allow re-distribution of theclothes and at the same time the unbalance motor 13!? rotates star cam132. The rotation of the star cam bends leaf spring 133 (Fig. 1) andafter a predetermined time interval the spring snaps back resetting theswitch 123 to its original position. This resetting of the unbalanceswitch deenergizes the unbalance timer motor and completes again thecircuit of the spin solenoid. The machine then again attemps toaccelerate to extraction speed. With this arrangement, it is possiblethat the machine may attempt acceleration to extraction speed severaltimes before finally attaining a balanced clothes load permitting smoothvibration free performance. But ultimately it will attain that balancedload condition, and severe vibration can never occur since high speedoperation is terminated whenever objection 17 able excursion of the tubwith the respect to the base occurs.

Throughout the spin period, the sequence timer motor 62 is in operationto advance the sequence control, and, of course, the pump 55 isenergized so that liquid extracted from the laundry is discharged to thedrain. Upon conclusion of this extraction period, the sequence controlswitches are again returned to position to cause the machine to refillwith rinse liquid and to operate at tumbling speed. The rinse fill andrinse operations are identical with those previously described.Preferably, and as shown on the sequence control chart, a third rinseoperation is provided before commencement of the final drain period atpoint 23 on the scale of the sequence control. This final drain ispreparatory to the final spin dry or centrifugal extraction operationimmediately preceding the application of heat for the final drying.Throughout the final extraction and drying periods, of course, thesequence control switch 67 is closed,.thereby energizing the pump 55.The centrifugal extraction is controlled, as previously described, byenergizing spin solenoid 32 through cam actuated switch 73 and theunbalance switch 123. The sequence control timer remains in operationunder the control of sequence control switch 72 in the manner previouslydescribed. The final centrifugal extraction periods ends at point 27 onthe cam chart when cam actuated switches 66 and 73 open.

If the operator desires to terminate further machine operation, the omitdry button 10 may be depressed, and then when the machine concludes thefinal extraction period further operation will cease. However, assumingthat the omit dry button is not depressed, the machine will go into thefinal drying period automatically and that period will be conducted asdescribed above so that heat is applied to extract substantially all ofthe moisture from the articles of clothing. The machine is conductedinto the dry period by the switch sequence control switches 65 and 72,the switch 65 closing slightly before the final spin period is ended andthe switch 72 being closed throughout the final spin period. After themachine proceeds into the dry period, the energization of the twoheaters 35 and 36 and the duration of the drying period itself iscontrolled by the single level thermostat 57 acting in conjunction withthe sequence control mechanism 56 as described above.

Incidently, referring to Fig. it will be noted that the control systemincludes an indicator light 134 for giving a visual indication of theoperation of the machine. This lamp 134 is so connected that it isenergized both during the washing and drying operations of the machineand it may, for example, be positioned behind the sequence control dial12 so as to illuminate it during the machine operation. Specifically, toeffect that result the lamp 134 is connected between the line 86 and theneutral line 78. Connected in this manner the lamp is energized throughthe sequence control switch 66 during the washing operation, and thesequence control switch 65 during the drying operation.

While in accordance with the patent statutes we have described what atpresent is considered to be the preferred embodiment of our invention,it will be obvious to those skilled in the art that various changes andmodifications.

may be made therein without departing from the invention and we,therefore, aim in the appended claims to cover all such changes andmodifications as fall within the true spirit and scope of our invention.

What we claim as new and desire to secure by Letters Patent of theUnited States is:

1. Clothes drying apparatus comprising clothes tumbling means, a pair ofelectrical heating units, and a control system comprising a thermostatresponsive to the temperature within said apparatus and having a normalposition and a tripped position, said thermostat opening to said trippedposition at a predeterminedhigh temperature and resetting to said normalposition at a predetermined lowertemperature, a sequence controlmechanism including a timer and a plurality of switches operated by saidtimer, and means including said thermostat and said sequence controlmechanism for energizing both of said heating elements simultaneously,said elements being arranged to provide heat to said thermostat untilsaid thermostat trips a first time in response to the heat from saidelements, said means energizing only one of said elements thereafterupon resetting of said thermostat, said one energized element beingarranged to provide heat to said thermostat until it trips a secondtime, said means deenergizing said one element too and terminating thedrying operation when said thermostat trips the second time in responseto the heat from said one element alone.

2. Clothes drying apparatus comprising clothes tumbling means, a motorfor driving said clothes tumbling means, a pair of electrical heatingunits, and a control system for said motor and said heating elements,comprising a thermostat responsive to the temperature within saidapparatus and having a normal position and a tripped position, saidthermostat opening to said tripped position at a predetermined hightemperature and resetting to said normal position at a predeterminedlower temperature, a sequence control mechanism including a timer and aplurality of switches operated by said timer, means including saidthermostat and said sequence control mechanism rorenergizing both ofsaid heating elements simultaneously, said elements being arranged toprovide heat to said thermostat until said thermostat trips a firsttime, said means energizing only one of said elements thereafter uponresetting of said thermostat, said one energized element being arrangedto provide heat to said thermostat until it trips a second time, saidmeans de-energizing said one element too when said thermostat trips asecond time, and means including said sequence control mechanism forenergizing said drive motor throughout the entire operation of theheating elements and for a timed cool-down period thereafter.

3. Clothes drying apparatus comprising clothes tumbling means, a pair ofelectrical heating elements, and a control system comprising athermostat responsive to the temperature within said apparatus andhaving a normally closed set of contracts, said thermostat opening to atripped position at a predetermined high temperature and resetting toits normal position at a predetermined low temperature, a sequencecontrol mechanism including a timer, heater circuit means for energizingsaid heating elements, said heater circuit means including said normally closed set of thermostat contacts and heater switch meanscontrolled by said sequence control mechanism, with the circuit to oneof said heating elements including a first switch operated by saidtimer, said heater circuit means being arranged to energize both of saidheating elements simultaneously until said thermostat trips a first timein response to the heat from both of said elements, and means responsiveto the first tripping of said thermo stat for advancing said timer toopen said first timer operated switch, thereby to cause said heatercircuit means to energize only the second of said heating elements tocontinue the drying action upon the resetting of said thermostat, andresponsive to the second tripping of said thermostat caused by the heatfrom said second element only for advancing said timer to open saidheater switch means, whereby said heater circuit is completelydisconnected for terminating the drying operation.

4. Clothes drying apparatus comprising a pair of electrical heatingelements, a clothes tumbling drum, a drive motor for driving saidclothes tumbling drum, and a control system comprising a thermostatresponsive to the temperature within said apparatus and having anormally closed set of contacts, said thermostat opening to a trippedtemperature, a sequence control mechanism including a timer, a motorcircuit controlled by said sequence control mechanism for energizingsaid drive motor throughout the drying operation, heater circuit meansfor energizing said heating elements, said heater circuit meansincluding said normally closed set of thermostat contacts and heaterswitch means controlled by said sequence control mechanism, with thecircuit to one of said heating elements including a first switchoperated by said timer, said heater circuit means being arranged toenergize both of said heating elements simultaneously until saidthermostat trips a first time in response to the heat from both of saidelements; and means responsive to the first tripping of said thermostatfor advancing said timer to open said first timer operated switch,thereby to cause said heater circuit means to energize only the secondof said heating elements to continue the drying operation upon theresetting of said thermostat, and responsive to the second tripping ofsaid thermostat caused by the heat from said second heating element onlyfor advancing said timer to open said heater switch means, and a secondswitch operated by said timer subsequent to the opening of said heaterswitch means for de-energizing said motor circuit and terminating theoperation of said machine.

5. Clothes drying apparatus com rising clothes tumbling means, a pair ofelectrical heating elements, and a control system com rising athermostat responsive to the temperature within said apparatus andopening to a tripped position at a predetermined high temperature andresetting to a normal position at a predetermined lower temperature,said thermostat having a first nor mally closed set of contacts and asecond normally o en set of contacts, a sequence control mechanismincluding ing a timer and a plurality of switches operated by saidtimer, heater circuit means for energizing said heating elementsincluding said normally closed set of thermo stat contacts and heaterswitch means controlled by said sequence control mechanism, with thecircuit to one of said heating elements including a first one of saidtimer operated switches, said heater circuit means being'arranged toenergize both of said heating elements simultaneously until saidthermostat trips a first time in response to the heat from both of saidelements, a timer circuit for energizing said timer closed by saidnormally open set of thermostat contacts when said thermostat is in saidtripped position, said timer being arranged to open said first timeroperated switch when energized by the first tripping of said thermostat,thereby to cause said heater circuit means to energize only the secondof said heating elements and not said one heating element upon theresetting of said thermostat, and said timer being arranged to operate asecond of said timer operated switches to open said heater switch meanswhen said timer circuit is again energized by the second tripping ofsaid thermostat res onsive to the heat from said second element alone,thereby to disconnect said heater circuit means and terminate the dryingoperation.

6. The combination of claim including a second timer circuit forenergizing said timer, said second timer circuit including a third oneof said timer operated switches, said third switch being closed for apredetermined interval upon the advance of said timer by the firsttripping of said thermostat thereby to lock in said timer long enough toinsure opening of said first timer operated switch, and said thirdswitch being again closed upon the subsequent advance of said timer bythe second tripping of said thermostat thereby to lock in said timeronce more and insure the opening of said second timer operated switch.

7. Clothes drying apparatus comprising clothes 'tuinbling means, a pairof electrical heating elements, and a control system comprising athermostat responsive to the temperature within said apparatus andopening to a tripped position at a predetermined high temperature andresetting to a normal position at a predetermined lower temperature,said thermostat having a first nor mally closed set of contacts and asecond normally opened pair of contacts, a sequence control mechanismincluding a timer and a plurality of switches operated by said timer, aheater relay having contacts and an operating coil, a relay coil circuitincluding a first of said timer operated switches, said first switchbeing closed at the start of the drying operation to close said relay,heater circuit means including said normally closed set of thethermostat contacts and said relay contacts for energizing said heatingelements, with the circuit to one of said heating elements including asecond of'sa'id timer operated switches, said heater circuit meansenergizing both of said heating elements simultaneously until saidthermostat trips a first time in response to the heat supplied by bothelements, a timer circuit for energizing said timer closed by saidnormally open set of the thermostat contacts when said thermostat is insaid tripped position, said timer being arranged to open said secondtimer operated switch when energized by the first tripping of saidthermostat, whereby said heater circuit means energizes only the secondof said heating elements upon the resetting of said thermostat tocontinue the drying operation, and said timer being arranged to opensaid first timer operated switch when said timer circuit is againenergized by the second tripping of said thermostat responsive to theheat from said second heating element alone, thereby to de-energize saidrelay coil and open said heater circuit means.

8. Clothes drying apparatus comprising a pair of electrical heatingelements, a clothes tumbling drum, a drive motor for driving saidclothes tumbling drum, and a control system comprising a thermostatresponive to the temperature within said apparatus and opening to atripped position at a'predetermined high temperature and resetting to anormal position at a predetermined lower temperature, said thermostathaving a first normally closed set of contacts and a second normallyopen set of contacts, a sequence control mechanism including a timer anda plurality of switches operated by said timer, a heater relay havingcontacts and an operating coil, a relay coil circuit including a firstof said timer operated switches, said first switch being closed at thestart of the drying operation to close said relay, a motor circuit forenergizing said drive motor throughout the drying operation, said motorcircuit including a second of said timer operated switches, heatercircuit means including said normally closed set of thermostat contacts.and said relay contacts for energizing said heating elements, with thecircuit to one of said heating elements including a third one of saidtimer operated switches, said heater circuit means energizing both ofsaid heating elements simultaneously until said thermostat trips a'firsttime in response to the heat supplied by both elements, a timer circuitfor energizing said timer closed by said normally open set of thethermostat contacts when said thermostat is in said tripped position,said timer being arranged to open said third timer operated switch whenenergized by the first tripping of said thermostats, whereby said heatercircuit means energizes only the second of said heating elements uponthe resetting of said thermostat to continue the drying operation, andsaid timer being arranged to open said second timer operated switch andthen said first timer operated switch when said timer circuit is againenergized by the second tripping of said thermostat responsive tothe'heat from said second heating element alone, thereby to de-energizefirstsaid relay coil and subsequently said motor circuit forde-energizing first said second heater and then said drive motor toterminate the drying operation.

9. The combination of claim 8 including a second timer circuit forenergizing said'timer, said secondtimer circuit including a fourth one.of said timer operated switches, said fourth switch being closed for apredetermined interval upon the advancing of said timer by the firsttripping of said thermostat, thereby to lock in said timer long enoughto insure opening of said third timer operated switch, and said fourthswitch being again closed upon the subequent advance of said timer bythe second tripping of said thermostat, thereby to lock in said timeronce more and insure the opening of said first and second timer operatedswitches.

References Cited in the file of this patent UNITED STATES PATENTSGorsuch Apr. 25, 1950 Kaufiman Apr. 24, 1951 Clark Dec. 16, 1952Robinson et a! May 10, 1955 Morrison Dec. 25, 1956

